Phosphorus pentabromide solubility

Niobium Pentabromide, NbBrs.—This is the only bromine compound of niobium hitherto prepared. It is obtained by the action of bromine vapour on the coarsely powdered metal,2 or on a mixture of niobium pentoxide and carbon in the absence of air.2 In the latter case some of the oxybromide is also formed. Niobium pentabromide is a fine, purple-red powder, very similar to red phosphorus in appearance. The fused substance forms garnet-red prisms. On being strongly heated it becomes yellow, and volatilises. It melts at about 150° C., and distils undecomposed in an inert atmosphere at about 270° C. It can be distilled unchanged in an atmosphere of nitrogen or carbon dioxide. It is very hygroscopic, hydrolyses rapidly in damp air, and is decomposed by water with a hissing noise and considerable evolution of heat into niobie add and hydrobromic add. It is soluble in absolute alcohol and in dry ethyl bromide. 

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